GlaxoSmithKline's diabetes drug Avandia has been ordered off shelves in Europe, and U.S. regulators have further restricted its use because of heart attack risks.

The European Medicines Agency said Thursday it was pulling its authorization for selling the Type 2 diabetes drug.

The U.S. Food and Drug Administration also said patients will only be able to get a new prescription for Avandia if their blood sugar levels can't be controlled with other medications.

"Although the European Medicines Agency went further by actually [suspending] marketing of the drug, both regulatory decisions result in essentially the same outcome — virtually complete elimination of the use of this drug by patients around the world," said Dr. Steve Nissen of the Cleveland Clinic.

Nissen published the first paper linking Avandia to heart risks.

The heart attack risks remain unclear, said Dr. Janet Woodock, director of the FDA's Center for Drug Evaluation and Research.

GSK stops all Avandia marketing

"As a matter of prudence, we are restricting access," Woodock told reporters in a conference call. "We are not withdrawing the drug at this time because there is considerable uncertainty about this signal and whether or not it's valid."

GSK issued a statement Thursday saying it will voluntarily stop marketing the drug, known generically as rosiglitazone, in all countries.

"The company continues to believe that Avandia is an important treatment for patients with Type 2 diabetes and is now working with the FDA and EMA to implement the required actions," said GlaxoSmithKline's chief medical officer, Dr. Ellen Strahlman.

Patients taking Avandia are advised not to stop taking the drug without discussing it with their health-care provider, since stopping medications can cause poorer diabetes control with high blood sugar levels.

The marketing restrictions apply in Canada.

"In Canada, labelling revisions are currently under review by Health Canada to add a Serious Warning and Precautions box to the product monographs of rosiglitazone-containing medicines," GSK said in an email.

"Promotion of the Avandia franchise, effective immediately, is suspended in Canada. However, the product continues to be available to Canadian health-care professionals and patients."

Alternatives available

"People taking Avandia should go to their doctor and ask, 'Should I be on this drug?'" said Dr. David Juurlink, a researcher at Sunnybrook Health Sciences Centre in Toronto, who conducted an earlier large study comparing Avandia with a similar diabetes drug, Actos, or pioglitazone.

"I think the answer in virtually every instance is going to be no, because there are alternatives out there that do not seem to confer the same cardiac risks as Avandia," he added in an interview.

Health Canada said Thursday it is aware of the decisions by regulators in the U.S. and Europe.

"We have already taken action on this drug and are currently considering further measures," Health Canada said in an email. "We will take the recent announcements by the FDA and EMA into consideration."

In 2007, Health Canada issued usage restrictions on Avandia due to cardiovascular risks. At that time, the health agency said Avandia was no longer approved for use alone to treat Type 2 diabetes, nor approved for use with a sulphonylurea drug except when the drug metformin is "contra-indicated," or not tolerated.

Juurlink said he hopes Health Canada follows the move by the European Medicines Agency and removes Avandia from the market.

"I think what the FDA has effectively done is allow this drug to die a slow, painful death rather than putting it out of its misery more quickly. And in the process, they have allowed large numbers of people to continue to use it, and I think that that's difficult to justify," Juurlink said.

Avandia is used to treat Type 2 diabetes, the most common form of the disease, which is linked to obesity and afflicts 200 million people worldwide. This form of diabetes occurs when the body does not make enough insulin or cannot effectively use what it manages to produce.